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CDaoRecordset & Class Wizard

liux012897
liux012897 asked
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Last Modified: 2013-11-20
When I use Class Wizard to derive a class from CDaoRecordset, I can set the type to be either "snapshot" or "dynaset".  From the file generated by Class Wizard, the only difference between these two types are that the variable m_nDefaultType is initialized differently.  
However, if I derive a "snapshot" class and manually change the value of the variable m_nDefault to use it as a "dynaset", I got "operation not supported error".
Yes, I did change the variable before I open the record set and I also tried to supply arguments to the Open() function to make sure it is opened as a "dynaset".
Anyway, this behavior seems strange.  I suspect that when the Class Wizard created the "snapshot" class, it also registered its "type" somewhere so that it can only be used as a "snapshot".  But I don't know much about OLE or whatever topics related to this.
Any explanation will be appreciated.
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I think the protected member variable you are referring to is m_nDefaultType.  This is just what it says, the default, if none is specified in the Open() call.  The actual type that is used is set in the member variable m_nOpenType, which is set in Open().  Setting the open type explicitly to dbOpenDynaset in the Open() call should work.  Note that the type specifiers for DAO are differnt that ODBC.  They do not interchange.

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Commented:
The problem is, I did try to open it by setting the type to dbOpenDynaset in the Open() call and get the same message "operation not supported". Just in case, I am going to check it one more time.

Author

Commented:
Sorry, my mistake.  I just chekced, there is no such problem, I must have done something wrong when I "discovered" this problme.
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